JPS61176111A - Manufacture of compound semiconductor thin film - Google Patents

Abstract

PURPOSE:To manufacture the compound semiconductor thin film of good quality in an excellent reproducible manner as well as to enable to manufacture a heterointerfaced compound semiconductor film having a steep compositional change. CONSTITUTION:A GaAs single crystal substrate 109 is provided on a substrate holder 108, hydrogen gas and arsine gas are fed into a reaction furnace 102 from a gas system 110 as carrier gas. The light source 105 of argon ion laser is turned ON under the above-mentioned condition, and an ultrathin oxide film is removed and a clean surface is obtained by projecting a visible laser beam on the substrate surface. Then, the laser beam is cut off, the vapor of organic metal compound such as trimethylgallium and the like is introduced from a gas system 101 as the bubbling gas of hydrogen gas, the switch of argon ion laser is turned ON, the argon ion laser is made to irradiate on the surface of the substrate, and the temperature of the substrate is raised. Also, nitrogen gas is blown on the back side of the substrate at the same time through a pipe plate 111, the rise in temperature of the substrate holder is prevented by heat conduction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a compound semiconductor thin film.

[Jukin technology]

In recent years, organometallic compounds (e.g. trimethyl gallium (TMez), diethyl zinc) have been (
DIZ? 1. ) etc.) and -77 (k8H,) to 7.
.

Chemical vapor deposition method C in which a predetermined amount of hydride such as hydrogen chloride (H, S) is mixed and a thin film is grown on a substrate with matching lattice constants.
(hereinafter referred to as MOOVD method) is being actively researched. This MO(!VD method is a companion to the liquid-phase Evita-Kensharu method (I, PK method), which is conventionally used in the production of semiconductor lasers, because it allows the formation of thin parts over a large area and is superior in mass productivity. It is considered to be advantageous in terms of yield and cost compared to conventional MO-OVD methods, which use high frequency heating, heating with a resistive heat source, heating with an infrared lamp, etc. Epitaxial growth was carried out by flowing source gas onto a JIg plate heated to approximately 771'l.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, the gas around the substrate is also heated and reaches the substrate surface while undergoing a decomposition reaction in the gas/l'' gas phase, so the type and amount of intermediate products in the gas phase h =
- However, there is a problem that the reproducibility of the film quality is poor.

Furthermore, for example, when forming a heterojunction such as 侃hs/At aahs, it takes time to replace the raw material gas introduced into the reactor, and during that time, residual gas in the reaction tube and gas piping is removed. Different formations of h=, m@*f are performed t
Therefore, it is difficult to form a film with a steep compositional change.

The present invention is intended to solve these problems, and its main purpose is to provide a method for manufacturing and obtaining a high-quality compound semiconductor thin film with good reproducibility, and to provide a method for manufacturing and obtaining a high-quality compound semiconductor thin film, which can also be used in optical elements such as semiconductor lasers. An object of the present invention is to provide a method that enables the production of a compound semiconductor thin film having a heterointerface with a steep compositional change necessary for forming a superlattice structure or the like.

Means for Solving the Problem of Time Loss] The method for producing a compound semiconductor thin film of the present invention uses a light source device having a wavelength range in the visible range to illuminate the surface of a substrate placed in a raw material gas atmosphere in a reactor. The method is characterized in that light is irradiated and at the same time cooling gas is blown onto the back surface of the substrate to form a thin film on the substrate.

[Effect]

According to the first configuration of the present invention, the visible wavelength light that serves as the heating source has almost no interaction with the raw material gas and the reactor material other than being absorbed by the substrate surface, so only the substrate surface is heated. be done. Therefore, in order to grow a thin film, and obtain an elementary excess of gas decomposition, rearrangement, and crystallization on the substrate surface, if conditions such as the temperature condition on the surface, the flow rate of raw material gas, and the gas pressure are kept constant, A thin film with the following characteristics can be obtained.

However, in order to form a heterojunction, if the light from the heating light source is blocked after the formation of a thin film with the composition fsl, decomposition of the source gas will not occur due to cooling from the back side of the substrate, and the gas components will be If the formation of a thin film with a composition of t42 is resumed by irradiating the same plate surface with the light of the heating light source after sufficiently exhausting the residual gas components, a difference in percentage will be formed at the heterojunction interface. Instead, it forms a steep heterojunction.

[Refreshing example]

Figure 1 shows a compound semiconductor thin film according to an embodiment of the present invention.
1 Schematic diagram of Isouden, inside 102 reactors! 1 for
08 board holder hZ#ly, *H hole/-upper cover 1
09 boards are installed. There is an optical window 103 on a part of the outer wall of the reactor 102, and from this window 4t of light from a light source 105 is converted to an appropriate size by a beam expander 104 and irradiated onto the surface of a substrate 109. .

, IIi board hole l- has a hollow structure, and the inside vibrator 111 is completely passed through, and the 10
Inert cooling gas can be blown through the gas system f of No. 7. Reference numeral 101 indicates a gas system for introducing an organometallic compound into the reactor 102, and numeral 110 indicates a gas system for introducing other raw material gases and carrier gases. This is an exhaust system that maintains the 106-scale reactant gas at the required pressure VC. Next, we will specifically discuss the implementation fII for manufacturing a gallium arsenide (GaAs) compound semiconductor thin film.
shows. On the board holder! /CGaA3 single crystal group [1
- set up and evacuate to high vacuum at 106; After that, 1
Hydrogen gas as a carrier gas from 10 to 58LM
flow rate sink.

Flow arsine (AJH8) gas f 20 to 508 ccM. In this state, use the 105 light source as the light source, turn on the switch of the argon ion laser, and turn on the S* coating surface laser beam (wavelength d).
457.9 to 514.5 m multi-line) to remove the extremely thin acid oxide on the surface of the GtLA8 substrate and expose the clean surface. Laser light output: 18W, substrate surface: 90W
The temperature rises from 0 to 1000°C. Next, turn off the laser beam and
From 01, organometallic compounds such as trimethyl gallium (TMGα) and triethyl gallium (TBGα) were kept at a constant temperature and their vapor was introduced into the reactor using hydrogen gas as a bugling gas, and the gas pressure was set at f1 to 100Toff K-U. Adjust the pumping speed to keep the pump busy. Once the gas flow rate and gas pressure are adjusted to the desired level, the argon ion laser switch 105 is turned on.

Since the laser beam has a multi-line wavelength of 457.9 to 514.5 m and is in the visible light range, absorption by gas molecules is not at all possible, and most of the output is absorbed by the surface of the Gaks substrate 109. The temperature of the substrate surface is 900-1000
"GK is raised. The temperature can be kept constant by adjusting the output of the argon laser. To be sure, at the same time as the laser beam irradiation, nitrogen gas from 107 is blown onto the back side of the substrate through pipe f of 111, and the temperature is The temperature of the substrate holder hz due to conduction
prevent it from rising. By this method, λh on the substrate surface
t becomes a high temperature state, AsH3 gas hexagram and T M (ka
Organic metals such as 1N continue to decompose and undergo chemical reactions until they reach the surface of the base 1N, and a GCL 1g single crystal grows from the next reaction process on the substrate surface.

侃((lW3)3+ks H3-1→杷AJ+3
CH, ↑OH, b = adsorption coefficient is small, so most of it becomes gas and flies away. Therefore, when conventional high-frequency heating or resistance heating is used, the gas temperature around the substrate becomes 500 to 600 degrees centigrade over a certain range.

The reproducibility of the film quality is several times better than under the condition where A8H and TMGα undergo a gas phase reaction fb in a gas, and then undergo a chemical reaction on the camphor board surface to grow a single crystal. In addition, organometallic compounds containing other elements of the progenitor group, V
If an appropriate amount of raw material gas containing group elements is mixed, ktL3a can be obtained.
AJ, Eng 5 (kl Aa, ■n Chz AJ P
It is possible to produce mixed crystal systems such as

Next, we will discuss the case of manufacturing a heterojunction of aa A8/At G (LAJ). After manufacturing a GrL kg thin layer by the method described above, the laser beam 105 is blocked. From that point on, a certain Upon cooling, the surface temperature of the #F group immediately decreases, and the growth of the thin film stops.After that, an organometallic compound such as trimethylaluminum (TMAt) is introduced, and the gas flow conditions are adjusted to produce a ktσI thin film.

After the gas flow rate and gas pressure are stabilized, kl Chz A8
Irradiation is performed with laser light whose output is adjusted so that the substrate temperature corresponds to the thin film growth conditions. The result (klZAJ/Aj(k
A perfectly controlled heterojunction is formed at the zυ interface.

Even when doping impurities to form a multilayer structure, it is possible to obtain a good P-N junction using exactly the same procedure.

〔Effect of the invention〕

As described above, according to the present invention, the surface of the XE plate is heated to control the decomposition and crystallization reactions on the substrate surface, and the reproducibility is excellent compared to the conventional MO-CVD method. This has the effect of dramatically improving performance.

Furthermore, since the formation of the heterojunction interface requires individual control of the production of the laminated films and no excess film is produced, a heterojunction with a steep compositional change can be produced.

Due to these effects, the compound semiconductor thin film manufacturing method of the present invention utilizes a semiconductor laser, a light receiving element, and a superlattice structure, and is useful for manufacturing optical elements such as low threshold lasers and short wavelength lasers, and for high-speed FFXT. Useful for manufacturing electrical devices.

[Brief explanation of the drawing]

The f41 diagram is a compound semiconductor thin film based on wood invention! A schematic diagram of the manufacturing device is shown. 101... Organometallic compound introduction gas system 102.
... Reactor sectional view 103 ... Optical window sectional view 104 ... Beam diameter adjustment optical system 105 ...
... Visible light source 106 ... Gas exhaust system 107 ... Cooling gas introduction system 108 ... Base bottle holder sectional view 109 ...
...Substrate 110...Material gas introduction system 111...Cooling gas introduction pipe and above Izuhara Suwa Seikosha Co., Ltd.

Claims (1)

[Claims] In the chemical vapor deposition method for forming a compound semiconductor thin film, a light source device having a visible wavelength range irradiates light onto the surface of a substrate placed in a raw material gas atmosphere in a reactor. A method for manufacturing a compound semiconductor thin film, comprising simultaneously blowing a cooling gas onto the back surface of the substrate to form a thin film on the surface of the substrate.